Study On The Coloration Modification Of Silk Protein And Its Mechanism

Silk is composed of silk fibroin and sericin wrapped around silk fibroin.Silk fabrics such as clothing are silk fibroin fabrics that remove most of the sericin.The silk gelatinization rate of silk fabric has a great influence on its quality.The training rate is the focus of the refined production of silk fabrics.At the same time,silk fibroin has become an important source of biomedical materials.It is important to study the chemical modification of silk fibroin to functionalize silk fibroin materials.The work of this thesis consists of two parts.The first part is to use the characteristic reaction of the coupling of tyrosine and diazonium salt in sericin to chromogenically modify the silk fibroin which is detached from the silk fabric,and then test the absorbance of the chromogenic solution to establish the absorbance.The test method for calculating the rate of the gelatin in the production process is estimated.Specifically,the standard curve of the absorbance-amino acid concentration of the amino acid mimicking protein-synthesizing color was plotted,and the stability of the diazonium salt,the effect of the coupling reaction pH on the coupled absorbance,and the precipitation after the sericin alkaline hydrolysis were studied.Composition,etc.The results show that the diazonium salt used for coupling color development should be prepared at 0 °C and can be stably stored.When the pH value of the coupling reaction is controlled at about 10,the coupling efficiency is higher;the maximum absorption of the coupling absorption spectrum of the scouring solution after alkali hydrolysis The peak is consistent with the tyrosine coupling absorption spectrum;the rate of deduction of the chromogenic salt coupling reaction with the diazonium salt is(3.6±0.05)% lower than the actual training rate.At the same time,it was found that the scouring liquid alkali hydrolysis precipitate does not contain a sericin component,and the precipitate is a scouring aid precipitate.In the second part of the thesis,the color development of silk fibroin protein was carried out by using aryl primary amine color-developing modifier.In order to study the modification conditions and the mechanism of Mannich reaction modification,a specific structure of aromatic primary amine dye was screened.Based on the preliminary work of amino acid mimicking silk fibroin modification,Mannich modification of tryptophan was carried out using aromatic primary amine dye as a modifier,and the product was separated and purified.The reaction products were analyzed by means of mass spectrometry,infrared spectroscopy and nuclear magnetic characterization.Analysis.The results show that the silk fabric has a color depth K/S value of 16 after being modified by the aromatic amine dye Mannich reaction.The K/S value after DMF stripping can still be as high as 14,indicating that the aromatic primary amine dye has been successfully reacted by Mannich.Modified to silk fibroin.At the same time,the experiment of tryptophan simulating the Mannich reaction of the aromatic primary amine dye showed that a new substance was produced,and the new substance point was clearly visible by thin layer chromatography.The ion peak with a mass-to-charge ratio of 570 was observed from the mass spectrum,and the infrared spectrum was observed.The primary ammonia double peak on the amine compound becomes a secondary ammonia single peak,and the nuclear magnetic H spectrum shows three methylene peaks,and the Mannich reaction acts on the tryptophan on the nitrogen atom of the anthracene ring.In summary,using the characteristic reaction of tyrosine and diazonium salt in the sericin to couple the color of the silk,the color modification of the silk sericin can be used to establish a test method for estimating the rate of the serication in the production process.The test result is(3.6±0.05)% lower than the actual training rate and can be used as a monitoring method for the silk refining process.The mannylamine dye was used as a modifier to modify the Mannich reaction of silk fibroin,and a strong modification product was formed on silk fibroin.It can be concluded that the tryptophan and primary amine dyes in silk fibroin have Mannich reaction modification,and the action site of Mannich reaction On the nitrogen atom of the anthracene ring on tryptophan.